I recently received a complaint from some folks downstream from me that the Xlib man pages don't mention which headers various functions appear in. Although it is certainly possible for folks to grep for it (assuming they are reasonably command-line savvy), that's really not the best way to get things done, particularly in this day and age when there are GUI IDE users who wouldn't know a CLI from a CFL. :-)
So please consider adding the header information to the pages wherever possible. (The specific page this particular developer was complaining about was the XLoadQueryFont man page.)

On Wed, Aug 4, 2010 at 15:18:58 -0700, bugzilla-daemon@freedesktop.org wrote:
> Although it is certainly possible for folks to grep for it (assuming they are
> reasonably command-line savvy), that's really not the best way to get things
> done, particularly in this day and age when there are GUI IDE users who
> wouldn't know a CLI from a CFL. :-)
>
those users probably shouldn't be programming for xlib anyway.